The present invention relates generally to an uninterruptible power supply that supplies power to a water pump during a power failure to ensure that water continuously flows through a water circuit to prevent freezing of the water.
Vapor compression systems include a compressor, a condenser, an expansion device and an evaporator that form a chiller. Refrigerant flows through the vapor compression system and defines a closed refrigerant circuit. Refrigerant is compressed to a high pressure in the compressor and then flows through the condenser, where the refrigerant rejects heat to a fluid medium. The refrigerant then is expanded to a low pressure in the expansion device and flows through the evaporator. In the evaporator, the refrigerant accepts heat from water, cooling the water and heating the refrigerant. The refrigerant then reenters the compressor, completing the cycle.
The water flows through a closed water circuit and is pumped through the water circuit by a water pump. The water cooled in the evaporator is used to provide a cooling function downstream from the evaporator. After providing the cooling function, the water returns to the evaporator and is again cooled, completing the cycle.
The water in the water circuit can also be heated in a boiler during a heating mode. The heated water is then used to heat a space. The water then returns to the boiler and is again heated, completing the cycle.
If a power failure occurs, both the compressor and the water pump stop operating, and the flow of refrigerant and water, respectively, stops. If the water flow through the water circuit stops, the water can possibly freeze and expand, possibly damaging the equipment and piping in the water circuit.
Additionally, the power failure would generate a compressor failure alarm because the motor of the compressor is not operating. However, this is disadvantageous because the compressor motor has not failed. Therefore, an unnecessary maintenance call would be made.
Hence, there is a need in the art for an uninterruptible power supply that supplies power to a water pump in the event of a power failure to ensure that water continuously flows through a water circuit to prevent freezing of the water and that overcomes the drawbacks and shortcomings of the prior art.